Hello everyone i'm doing Poor man's AR for some time and today i decided to precipitate gold from all that jars with solution that i made in last 3 weeks. After adding SMB i got white crystals i deducted it is CuCl it's soluble in water and very soluble in HCl (which i would like to save cause it's not easy to get). So i added warm H2O and CuCl crystals dissolved but i got silverish precipitate (don't know what it is but it's hard to belive it's silver cause i processed only pcb's which had gold pads or traces and gold plated connectors. And also theres a bit of white powder (i guess CuCl which hadn't dissolved in water. a a little cloud of brownish powder which i think is gold XD. Most of time i collecte gold foils floating around solution and didn't bother about gold which dissolved but now i'd like to get it out too. All solutions stayed the same colour. Also one solution from PCB's which was beautiful green just as you can see on yt channels etc after adding SMB turned black/brown it would be ok but it is like 2h or more after adding great that some a little bit of brownish powder settled down but solution stays the same colour, shouldn't it slowly get to blue one ? I was adding urea untill there was no more bubbling before adding SMB. Did i messed up something guys ? Are my deductions about CuCl and other precipitates correct? Please help me i'm new in this field ^^ i got a lot of e-scraps for free frome the place where i work so i started getting interested in recovery ^^.

Well stannous chloride test is possitive, i threw my pcb's into jar poured Hcl over them and added NaNO3 over time copper and gold from pcbs dissolved than i added urea untill no more fizzing to denox, and than added a little bit more than half of the small spoon of SMB, came back from work now it's been like 10h i can see on the bottom a little bit of brown powder and few CuCl crystals, but solution still stays black/dark brown . I know that CuCl preticipated in another solution cause it was "dirty" gold plated pins solution, now as i look at that one i can see little shining powder in between of what's left but i think it's mostly copper. I was thinking about collecting all preticipate from all jars into one than adding HCl to see whats left and eventully doing AR with just what preticipated but i'm not sure. I'm not sure about my stnnous chloride either cause once it shows purple color, and after some time of doing othing i test the same solution and i get firstly brownish and then clear and jar is just sitting there nothing preticipates or anything. Yea maybe i shouldn't do few batches but i don't have a lot of free time and e-waste is starting to acumulate here so i'm trying to do as much as i can when i got time . Maybe my stannous chloride went bad ? But i've made it like 2weeks ago, with 98%Tin.

Well i'm just worried that i will do something that will waste my gold ...

Boards from Shock sensors it looks kinda like that http://www.123securite.fr/detecteur-ouv ... KC8M-D.cfm but it have a lot of gold traces and pads on the other side (and of course there are no components on it) some boards from alarms, (small broken down pieces with gold traces like bar code "production scrap" ) and few from some meters i'm not sure but few are from some train sensors and few from if i'm correct camera parts. I had to bath them in 2 parties, cause i couldn't fit all in one batch.

You stated you already collected some foils. My guess is the little bit of dust on the bottom is all your gold.

Stannous can give a false positive and from your description, that would be my guess.

I think you can heat the solution and then let it cool to drive off the SMB and then retest your solution. It sounds like you have used a lot of SMB so hopefully someone else will chime in but thats what I would do.

I suspect you are going to need many kilos of boards to get a decent amount of gold and that is why kernels is asking you the amounts you are working on, visible gold plating is usually very thin so if you have only done a kilo you may only have a gram of gold or even possibly less.